It has now long been recognized that there is a cause-and-effect relationship between prolonged and/or repeated exposure to UV light and premature aging of the skin. In general terms, excessive exposure to the sun contributes substantially to premature decline in the quality and quantity of elastin and collagen in the skin, as well as hypertrophy of the epidermis. These changes are manifested externally by typical signs of aging, such as deep lines and wrinkles, loss of elasticity, skin dryness and unevenness, and increased frequency of blotches, pigmented spots, and benign as well as malignant neoplasms.
It has also been proposed that to a large extent the damage done is due to the generation of free radical species on the skin by UV radiation. Free radicals, if uncontrolled, may rapidly, and randomly, react with molecules in their vicinity, giving rise to toxic products that can interfere with the body's normal physiological processes. The cumulative effects of these reactions can, and probably always eventually do, overwhelm the body's normal repair mechanisms. Free radical reactions are widely considered to have a major contributory effect on the natural aging process.
It has been recognized in recent years that the presence of oxygen radicals on the skin is probably responsible for a number of the undesirable effects of exposure to the sun. For example, the aging phenomenon generally observed throughout the body is frequently observed prematurely on the skin as a result of photoaging, which accelerates the process of deterioration of elastin and collagen, among other effects. There is also an increased risk of skin cancer of all types. In response to this need, the skin care industry has continued to seek new and more effective means for combating the these processes. Antioxidants in general have not, to date, been shown to have an in vivo protective effect on human skin against a routine, non-acute exposure to sun, and there has been much skepticism as to whether antioxidants can really be expected to have measurable effect on the aging process. There thus continues to be a need for a composition which is effective in the treatment, prevention, or even reversal, of the symptoms of photoaging.